Only schedule termination task if an unconnected MP bot is dead
Only schedule termination task if an unconnected MP bot is dead

Previously this was happening no matter what, meaning we were hardly
giving any chance to MP bots to actually connect.

Bug: 717769
Review-Url: https://codereview.chromium.org/2951023002

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py